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Sandonà M, Saccone V. Post-translational Modification in Muscular Dystrophies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1382:71-84. [DOI: 10.1007/978-3-031-05460-0_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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2
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Howard ZM, Dorn LE, Lowe J, Gertzen MD, Ciccone P, Rastogi N, Odom GL, Accornero F, Chamberlain JS, Rafael-Fortney JA. Micro-dystrophin gene therapy prevents heart failure in an improved Duchenne muscular dystrophy cardiomyopathy mouse model. JCI Insight 2021; 6:146511. [PMID: 33651713 PMCID: PMC8119181 DOI: 10.1172/jci.insight.146511] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 02/24/2021] [Indexed: 12/19/2022] Open
Abstract
Gene replacement for Duchenne muscular dystrophy (DMD) with micro-dystrophins has entered clinical trials, but efficacy in preventing heart failure is unknown. Although most patients with DMD die from heart failure, cardiomyopathy is undetectable until the teens, so efficacy from trials in young boys will be unknown for a decade. Available DMD animal models were sufficient to demonstrate micro-dystrophin efficacy on earlier onset skeletal muscle pathology underlying loss of ambulation and respiratory insufficiency in patients. However, no mouse models progressed into heart failure, and dog models showed highly variable progression insufficient to evaluate efficacy of micro-dystrophin or other therapies on DMD heart failure. To overcome this barrier, we have generated the first DMD mouse model to our knowledge that reproducibly progresses into heart failure. This model shows cardiac inflammation and fibrosis occur prior to reduced function. Fibrosis does not continue to accumulate, but inflammation persists after function declines. We used this model to test micro-dystrophin gene therapy efficacy on heart failure prevention for the first time. Micro-dystrophin prevented declines in cardiac function and prohibited onset of inflammation and fibrosis. This model will allow identification of committed pathogenic steps to heart failure and testing of genetic and nongenetic therapies to optimize cardiac care for patients with DMD.
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Affiliation(s)
- Zachary M. Howard
- Department of Physiology & Cell Biology and Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Lisa E. Dorn
- Department of Physiology & Cell Biology and Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Jeovanna Lowe
- Department of Physiology & Cell Biology and Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Megan D. Gertzen
- Department of Physiology & Cell Biology and Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Pierce Ciccone
- Department of Physiology & Cell Biology and Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Neha Rastogi
- Department of Physiology & Cell Biology and Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Guy L. Odom
- Department of Neurology and Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, University of Washington, Seattle, Washington, USA
| | - Federica Accornero
- Department of Physiology & Cell Biology and Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Jeffrey S. Chamberlain
- Department of Neurology and Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, University of Washington, Seattle, Washington, USA
| | - Jill A. Rafael-Fortney
- Department of Physiology & Cell Biology and Davis Heart and Lung Research Institute, College of Medicine, The Ohio State University, Columbus, Ohio, USA
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3
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Valera IC, Wacker AL, Hwang HS, Holmes C, Laitano O, Landstrom AP, Parvatiyar MS. Essential roles of the dystrophin-glycoprotein complex in different cardiac pathologies. Adv Med Sci 2021; 66:52-71. [PMID: 33387942 DOI: 10.1016/j.advms.2020.12.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 12/12/2020] [Accepted: 12/17/2020] [Indexed: 12/20/2022]
Abstract
The dystrophin-glycoprotein complex (DGC), situated at the sarcolemma dynamically remodels during cardiac disease. This review examines DGC remodeling as a common denominator in diseases affecting heart function and health. Dystrophin and the DGC serve as broad cytoskeletal integrators that are critical for maintaining stability of muscle membranes. The presence of pathogenic variants in genes encoding proteins of the DGC can cause absence of the protein and/or alterations in other complex members leading to muscular dystrophies. Targeted studies have allowed the individual functions of affected proteins to be defined. The DGC has demonstrated its dynamic function, remodeling under a number of conditions that stress the heart. Beyond genetic causes, pathogenic processes also impinge on the DGC, causing alterations in the abundance of dystrophin and associated proteins during cardiac insult such as ischemia-reperfusion injury, mechanical unloading, and myocarditis. When considering new therapeutic strategies, it is important to assess DGC remodeling as a common factor in various heart diseases. The DGC connects the internal F-actin-based cytoskeleton to laminin-211 of the extracellular space, playing an important role in the transmission of mechanical force to the extracellular matrix. The essential functions of dystrophin and the DGC have been long recognized. DGC based therapeutic approaches have been primarily focused on muscular dystrophies, however it may be a beneficial target in a number of disorders that affect the heart. This review provides an account of what we now know, and discusses how this knowledge can benefit persistent health conditions in the clinic.
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Affiliation(s)
- Isela C Valera
- Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee, FL, USA
| | - Amanda L Wacker
- Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee, FL, USA
| | - Hyun Seok Hwang
- Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee, FL, USA
| | - Christina Holmes
- Department of Chemical and Biomedical Engineering, Florida A&M University-Florida State University College of Engineering, Tallahassee, FL, USA
| | - Orlando Laitano
- Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee, FL, USA
| | - Andrew P Landstrom
- Department of Pediatrics, Division of Cardiology, Duke University School of Medicine, Durham, NC, USA; Department of Cell Biology, Duke University School of Medicine, Durham, NC, USA
| | - Michelle S Parvatiyar
- Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee, FL, USA.
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4
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Meyers TA, Townsend D. Cardiac Pathophysiology and the Future of Cardiac Therapies in Duchenne Muscular Dystrophy. Int J Mol Sci 2019; 20:E4098. [PMID: 31443395 PMCID: PMC6747383 DOI: 10.3390/ijms20174098] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/12/2019] [Accepted: 08/19/2019] [Indexed: 12/25/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a devastating disease featuring skeletal muscle wasting, respiratory insufficiency, and cardiomyopathy. Historically, respiratory failure has been the leading cause of mortality in DMD, but recent improvements in symptomatic respiratory management have extended the life expectancy of DMD patients. With increased longevity, the clinical relevance of heart disease in DMD is growing, as virtually all DMD patients over 18 year of age display signs of cardiomyopathy. This review will focus on the pathophysiological basis of DMD in the heart and discuss the therapeutic approaches currently in use and those in development to treat dystrophic cardiomyopathy. The first section will describe the aspects of the DMD that result in the loss of cardiac tissue and accumulation of fibrosis. The second section will discuss cardiac small molecule therapies currently used to treat heart disease in DMD, with a focus on the evidence supporting the use of each drug in dystrophic patients. The final section will outline the strengths and limitations of approaches directed at correcting the genetic defect through dystrophin gene replacement, modification, or repair. There are several new and promising therapeutic approaches that may protect the dystrophic heart, but their limitations suggest that future management of dystrophic cardiomyopathy may benefit from combining gene-targeted therapies with small molecule therapies. Understanding the mechanistic basis of dystrophic heart disease and the effects of current and emerging therapies will be critical for their success in the treatment of patients with DMD.
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Affiliation(s)
- Tatyana A Meyers
- Department of Integrative Biology and Physiology, Medical School, University of Minnesota, Minneapolis, MN 55455, USA
| | - DeWayne Townsend
- Department of Integrative Biology and Physiology, Medical School, University of Minnesota, Minneapolis, MN 55455, USA.
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5
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Parvatiyar MS, Brownstein AJ, Kanashiro-Takeuchi RM, Collado JR, Dieseldorff Jones KM, Gopal J, Hammond KG, Marshall JL, Ferrel A, Beedle AM, Chamberlain JS, Renato Pinto J, Crosbie RH. Stabilization of the cardiac sarcolemma by sarcospan rescues DMD-associated cardiomyopathy. JCI Insight 2019; 5:123855. [PMID: 31039133 PMCID: PMC6629091 DOI: 10.1172/jci.insight.123855] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 04/23/2019] [Indexed: 02/02/2023] Open
Abstract
In the current preclinical study, we demonstrate the therapeutic potential of sarcospan (SSPN) overexpression to alleviate cardiomyopathy associated with Duchenne muscular dystrophy (DMD) utilizing dystrophin-deficient mdx mice with utrophin haploinsufficiency that more accurately represent the severe disease course of human DMD. SSPN interacts with dystrophin, the DMD disease gene product, and its autosomal paralog utrophin, which is upregulated in DMD as a partial compensatory mechanism. SSPN transgenic mice have enhanced abundance of fully glycosylated α-dystroglycan, which may further protect dystrophin-deficient cardiac membranes. Baseline echocardiography reveals SSPN improves systolic function and hypertrophic indices in mdx and mdx:utr-heterozygous mice. Assessment of SSPN transgenic mdx mice by hemodynamic pressure-volume methods highlights enhanced systolic performance compared to mdx controls. SSPN restores cardiac sarcolemma stability, the primary defect in DMD disease, reduces fibrotic response and improves contractile function. We demonstrate that SSPN ameliorates more advanced cardiac disease in the context of diminished sarcolemma expression of utrophin and β1D integrin that mitigate disease severity and partially restores responsiveness to β-adrenergic stimulation. Overall, our current and previous findings suggest SSPN overexpression in DMD mouse models positively impacts skeletal, pulmonary and cardiac performance by addressing the stability of proteins at the sarcolemma that protect the heart from injury, supporting SSPN and membrane stabilization as a therapeutic target for DMD.
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Affiliation(s)
- Michelle S. Parvatiyar
- Department of Integrative Biology & Physiology and
- Center for Duchenne Muscular Dystrophy, UCLA, Los Angeles, California, USA
| | - Alexandra J. Brownstein
- Department of Integrative Biology & Physiology and
- Center for Duchenne Muscular Dystrophy, UCLA, Los Angeles, California, USA
| | - Rosemeire M. Kanashiro-Takeuchi
- Interdisciplinary Stem Cell Institute, University of Miami, Florida, USA
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, Florida, USA
| | | | | | - Jay Gopal
- Department of Integrative Biology & Physiology and
| | - Katherine G. Hammond
- Department of Integrative Biology & Physiology and
- Center for Duchenne Muscular Dystrophy, UCLA, Los Angeles, California, USA
| | - Jamie L. Marshall
- Department of Integrative Biology & Physiology and
- Center for Duchenne Muscular Dystrophy, UCLA, Los Angeles, California, USA
| | - Abel Ferrel
- Department of Integrative Biology & Physiology and
| | - Aaron M. Beedle
- Department of Pharmaceutical Sciences, Binghamton University State University of New York, Binghamton, New York, USA
| | | | - Jose Renato Pinto
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida, USA
| | - Rachelle H. Crosbie
- Department of Integrative Biology & Physiology and
- Center for Duchenne Muscular Dystrophy, UCLA, Los Angeles, California, USA
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
- Molecular Biology Institute, UCLA, Los Angeles, California, USA
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6
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Omentum acts as a regulatory organ controlling skeletal muscle repair of mdx mice diaphragm. Cell Tissue Res 2019; 377:269-279. [DOI: 10.1007/s00441-019-03012-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 03/06/2019] [Indexed: 12/18/2022]
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7
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Stretch-activated TRPV2 channels: Role in mediating cardiopathies. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:273-280. [PMID: 28546113 DOI: 10.1016/j.pbiomolbio.2017.05.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 05/17/2017] [Accepted: 05/19/2017] [Indexed: 02/06/2023]
Abstract
Transient receptor potential vanilloid type 2, TRPV2, is a calcium-permeable cation channel belonging to the TRPV channel family. Although this channel has been first characterized as a noxious heat sensor, its mechanosensor property recently gained importance in various physiological functions. TRPV2 has been described as a stretch-mediated channel and a regulator of calcium homeostasis in several cell types and has been shown to be involved in the stretch-dependent responses in cardiomyocytes. Hence, several studies in the last years support the idea that TRPV2 play a key role in the function and structure of the heart, being involved in the cardiac compensatory mechanisms in response to pathologic or exercise-induced stress. We present here an overview of the current literature and concepts of TRPV2 channels involvement (i) in the mechanical coupling mechanisms in heart and (ii) in the mechanisms that lead to cardiomyopathies. All these studies lead us to think that TRPV2 may also be an important cardiac drug target based on its major physiological roles in heart.
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Gonzalez JP, Kyrychenko S, Kyrychenko V, Schneider JS, Granier CJ, Himelman E, Lahey KC, Zhao Q, Yehia G, Tao YX, Bhaumik M, Shirokova N, Fraidenraich D. Small Fractions of Muscular Dystrophy Embryonic Stem Cells Yield Severe Cardiac and Skeletal Muscle Defects in Adult Mouse Chimeras. Stem Cells 2016; 35:597-610. [PMID: 27734557 DOI: 10.1002/stem.2518] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 09/10/2016] [Accepted: 09/26/2016] [Indexed: 01/10/2023]
Abstract
Duchenne muscular dystrophy (DMD) is characterized by the loss of the protein dystrophin, leading to muscle fragility, progressive weakening, and susceptibility to mechanical stress. Although dystrophin-negative mdx mouse models have classically been used to study DMD, phenotypes appear mild compared to patients. As a result, characterization of muscle pathology, especially in the heart, has proven difficult. We report that injection of mdx embryonic stem cells (ESCs) into Wild Type blastocysts produces adult mouse chimeras with severe DMD phenotypes in the heart and skeletal muscle. Inflammation, regeneration and fibrosis are observed at the whole organ level, both in dystrophin-negative and dystrophin-positive portions of the chimeric tissues. Skeletal and cardiac muscle function are also decreased to mdx levels. In contrast to mdx heterozygous carriers, which show no significant phenotypes, these effects are even observed in chimeras with low levels of mdx ESC incorporation (10%-30%). Chimeric mice lack typical compensatory utrophin upregulation, and show pathological remodeling of Connexin-43. In addition, dystrophin-negative and dystrophin-positive isolated cardiomyocytes show augmented calcium response to mechanical stress, similar to mdx cells. These global effects highlight a novel role of mdx ESCs in triggering muscular dystrophy even when only low amounts are present. Stem Cells 2017;35:597-610.
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Affiliation(s)
- J Patrick Gonzalez
- Department of Cell Biology and Molecular Medicine, Newark, New Jersey, USA
| | - Sergii Kyrychenko
- Department of Pharmacology, Physiology and Neuroscience, Newark, New Jersey, USA
| | - Viktoriia Kyrychenko
- Department of Pharmacology, Physiology and Neuroscience, Newark, New Jersey, USA
| | - Joel S Schneider
- Department of Cell Biology and Molecular Medicine, Newark, New Jersey, USA
| | - Celine J Granier
- Department of Pediatrics, Rutgers Biomedical and Health Sciences, Robert Wood Johnson Medical School, New Brunswick, New Jersey, USA
| | - Eric Himelman
- Department of Cell Biology and Molecular Medicine, Newark, New Jersey, USA
| | - Kevin C Lahey
- Department of Cell Biology and Molecular Medicine, Newark, New Jersey, USA
| | - Qingshi Zhao
- Department of Cell Biology and Molecular Medicine, Newark, New Jersey, USA
| | - Ghassan Yehia
- Genome Editing Core Facility, Office of Research Advancement, New Brunswick, New Jersey, USA
| | - Yuan-Xiang Tao
- Department of Cell Biology and Molecular Medicine, Newark, New Jersey, USA.,Department of Pharmacology, Physiology and Neuroscience, Newark, New Jersey, USA.,Department of Anesthesiology, Rutgers Biomedical and Health Sciences, New Jersey Medical School, Newark, New Jersey, USA
| | - Mantu Bhaumik
- Department of Pediatrics, Rutgers Biomedical and Health Sciences, Robert Wood Johnson Medical School, New Brunswick, New Jersey, USA
| | - Natalia Shirokova
- Department of Pharmacology, Physiology and Neuroscience, Newark, New Jersey, USA
| | - Diego Fraidenraich
- Department of Cell Biology and Molecular Medicine, Newark, New Jersey, USA
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9
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Aguettaz E, Lopez JJ, Krzesiak A, Lipskaia L, Adnot S, Hajjar RJ, Cognard C, Constantin B, Sebille S. Axial stretch-dependent cation entry in dystrophic cardiomyopathy: Involvement of several TRPs channels. Cell Calcium 2016; 59:145-155. [PMID: 26803937 DOI: 10.1016/j.ceca.2016.01.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 12/14/2015] [Accepted: 01/02/2016] [Indexed: 02/07/2023]
Abstract
In Duchenne muscular dystrophy (DMD), deficiency of the cytoskeletal protein dystrophin leads to well-described defects in skeletal muscle but also to dilated cardiomyopathy (DCM). In cardiac cells, the subsarcolemmal localization of dystrophin is thought to protect the membrane from mechanical stress. The dystrophin deficiency leads to membrane instability and a high stress-induced Ca(2+) influx due to dysregulation of sarcolemmal channels such as stretch-activated channels (SACs). In this work divalent cation entry has been explored in isolated ventricular Wild Type (WT) and mdx cardiomyocytes in two different conditions: at rest and during the application of an axial stretch. At rest, our results suggest that activation of TRPV2 channels participates to a constitutive basal cation entry in mdx cardiomyocytes.Using microcarbon fibres technique, an axial stretchwas applied to mimic effects of physiological conditions of ventricular filling and study on cation influx bythe Mn(2+)-quenching techniquedemonstrated a high stretch-dependentcationic influx in dystrophic cells, partially due to SACs. Involvement of TRPs channels in this excessive Ca(2+) influx has been investigated using specific modulators and demonstratedboth sarcolemmal localization and an abnormal activity of TRPV2 channels. In conclusion, TRPV2 channels are demonstrated here to play a key role in cation influx and dysregulation in dystrophin deficient cardiomyocytes, enhanced in stretching conditions.
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Affiliation(s)
- E Aguettaz
- Laboratoire de Signalisation et Transports Ioniques Membranaires (STIM CNRS ERL 7368), Equipe Transferts Ioniques et Rythmicité Cardiaque (TIRC), Université de Poitiers, 86073 Poitiers Cedex 9, France
| | - J J Lopez
- Laboratoire de Signalisation et Transports Ioniques Membranaires (STIM CNRS ERL 7368), Equipe Calcium et Microenvironnement des Cellules Souches (CMCS), Université de Poitiers, 86073 Poitiers Cedex 9, France
| | - A Krzesiak
- Laboratoire de Signalisation et Transports Ioniques Membranaires (STIM CNRS ERL 7368), Equipe Transferts Ioniques et Rythmicité Cardiaque (TIRC), Université de Poitiers, 86073 Poitiers Cedex 9, France
| | - L Lipskaia
- INSERM U955 and Département de Physiologie, Hôpital Henri Mondor, AP-HP, Université Paris-Est Créteil (UPEC), 94010 Créteil, France.,Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - S Adnot
- INSERM U955 and Département de Physiologie, Hôpital Henri Mondor, AP-HP, Université Paris-Est Créteil (UPEC), 94010 Créteil, France
| | - R J Hajjar
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - C Cognard
- Laboratoire de Signalisation et Transports Ioniques Membranaires (STIM CNRS ERL 7368), Equipe Transferts Ioniques et Rythmicité Cardiaque (TIRC), Université de Poitiers, 86073 Poitiers Cedex 9, France
| | - B Constantin
- Laboratoire de Signalisation et Transports Ioniques Membranaires (STIM CNRS ERL 7368), Equipe Calcium et Microenvironnement des Cellules Souches (CMCS), Université de Poitiers, 86073 Poitiers Cedex 9, France
| | - S Sebille
- Laboratoire de Signalisation et Transports Ioniques Membranaires (STIM CNRS ERL 7368), Equipe Transferts Ioniques et Rythmicité Cardiaque (TIRC), Université de Poitiers, 86073 Poitiers Cedex 9, France
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10
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Meyers TA, Townsend D. Early right ventricular fibrosis and reduction in biventricular cardiac reserve in the dystrophin-deficient mdx heart. Am J Physiol Heart Circ Physiol 2014; 308:H303-15. [PMID: 25485898 DOI: 10.1152/ajpheart.00485.2014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Duchenne muscular dystrophy (DMD) is a progressive disease of striated muscle deterioration. Respiratory and cardiac muscle dysfunction are particularly clinically relevant because they result in the leading causes of death in DMD patients. Despite the clinical and physiological significance of these systems, little has been done to understand the cardiorespiratory interaction in DMD. We show here that prior to the onset of global cardiac dysfunction, dystrophin-deficient mdx mice have increased cardiac fibrosis with the right ventricle being particularly affected. Using a novel biventricular cardiac catheterization technique coupled with cardiac stress testing, we demonstrate that both the right and left ventricles have significant reductions in both systolic and diastolic function in response to dobutamine. Unstimulated cardiac function is relatively normal except for a significant reduction in the ventricular pressure transient duration compared with controls. These biventricular analyses also reveal the absence of a dobutamine-induced increase in isovolumic relaxation in the right ventricle of control hearts. Simultaneous assessment of biventricular pressure demonstrates a dobutamine-dependent enhancement of coupling between the ventricles in control mice, which is absent in mdx mice. Furthermore, studies probing the passive-extension properties of the left ventricle demonstrate that the mdx heart is significantly more compliant compared with age-matched C57BL/10 hearts, which have an age-dependent stiffening that is completely absent from dystrophic hearts. These new results indicate that right ventricular fibrosis is an early indicator of the development of dystrophic cardiomyopathy, suggesting a mechanism by which respiratory insufficiency may accelerate the development of heart failure in DMD.
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Affiliation(s)
- Tatyana A Meyers
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, Minnesota
| | - DeWayne Townsend
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, Minnesota
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11
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Townsend D. Finding the sweet spot: assembly and glycosylation of the dystrophin-associated glycoprotein complex. Anat Rec (Hoboken) 2014; 297:1694-705. [PMID: 25125182 PMCID: PMC4135523 DOI: 10.1002/ar.22974] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 03/27/2014] [Indexed: 01/12/2023]
Abstract
The dystrophin-associated glycoprotein complex (DGC) is a collection of glycoproteins that are essential for the normal function of striated muscle and many other tissues. Recent genetic studies have implicated the components of this complex in over a dozen forms of muscular dystrophy. Furthermore, disruption of the DGC has been implicated in many forms of acquired disease. This review aims to summarize the current state of knowledge regarding the processing and assembly of dystrophin-associated proteins with a focus primarily on the dystroglycan heterodimer and the sarcoglycan complex. These proteins form the transmembrane portion of the DGC and undergo a complex multi-step processing with proteolytic cleavage, differential assembly, and both N- and O-glycosylation. The enzymes responsible for this processing and a model describing the sequence and subcellular localization of these events are discussed.
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Affiliation(s)
- Dewayne Townsend
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, Minnesota
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12
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Strakova J, Dean JD, Sharpe KM, Meyers TA, Odom GL, Townsend D. Dystrobrevin increases dystrophin's binding to the dystrophin-glycoprotein complex and provides protection during cardiac stress. J Mol Cell Cardiol 2014; 76:106-15. [PMID: 25158611 DOI: 10.1016/j.yjmcc.2014.08.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 08/14/2014] [Accepted: 08/16/2014] [Indexed: 01/05/2023]
Abstract
Duchenne muscular dystrophy is a fatal progressive disease of both cardiac and skeletal muscle resulting from the mutations in the DMD gene and loss of the protein dystrophin. Alpha-dystrobrevin (α-DB) tightly associates with dystrophin but the significance of this interaction within cardiac myocytes is poorly understood. In the current study, the functional role of α-DB in cardiomyocytes and its implications for dystrophin function are examined. Cardiac stress testing demonstrated significant heart disease in α-DB null (adbn(-/-)) mice, which displayed mortality and lesion sizes that were equivalent to those seen in dystrophin-deficient mdx mice. Despite normal expression and subcellular localization of dystrophin in the adbn(-/-) heart, there is a significant decrease in the strength of dystrophin's interaction with the membrane-bound dystrophin-associated glycoprotein complex (DGC). A similar weakening of the dystrophin-membrane interface was observed in mice lacking the sarcoglycan complex. Cardiomyocytes from adbn(-/-) mice were smaller and responded less to adrenergic receptor induced hypertrophy. The basal decrease in size could not be attributed to aberrant Akt activation. In addition, the organization of the microtubule network was significantly altered in adbn(-/-) cardiac myocytes, while the total expression of tubulin was unchanged in adbn(-/-) hearts. These studies demonstrate that α-DB is a multifunctional protein that increases dystrophin's binding to the dystrophin-glycoprotein complex, and is critical for the full functionality of dystrophin.
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Affiliation(s)
- Jana Strakova
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA
| | - Jon D Dean
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA
| | - Katharine M Sharpe
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA
| | - Tatyana A Meyers
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA
| | - Guy L Odom
- Department of Neurology, University of Washington, Seattle, WA, USA
| | - DeWayne Townsend
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA.
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13
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Proteomic profiling of the dystrophin-deficient mdx phenocopy of dystrophinopathy-associated cardiomyopathy. BIOMED RESEARCH INTERNATIONAL 2014; 2014:246195. [PMID: 24772416 PMCID: PMC3977469 DOI: 10.1155/2014/246195] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 02/16/2014] [Indexed: 01/07/2023]
Abstract
Cardiorespiratory complications are frequent symptoms of Duchenne muscular dystrophy, a neuromuscular disorder caused by primary abnormalities in the dystrophin gene. Loss of cardiac dystrophin initially leads to changes in dystrophin-associated glycoproteins and subsequently triggers secondarily sarcolemmal disintegration, fibre necrosis, fibrosis, fatty tissue replacement, and interstitial inflammation. This results in progressive cardiac disease, which is the cause of death in a considerable number of patients afflicted with X-linked muscular dystrophy. In order to better define the molecular pathogenesis of this type of cardiomyopathy, several studies have applied mass spectrometry-based proteomics to determine proteome-wide alterations in dystrophinopathy-associated cardiomyopathy. Proteomic studies included both gel-based and label-free mass spectrometric surveys of dystrophin-deficient heart muscle from the established mdx animal model of dystrophinopathy. Comparative cardiac proteomics revealed novel changes in proteins associated with mitochondrial energy metabolism, glycolysis, signaling, iron binding, antibody response, fibre contraction, basal lamina stabilisation, and cytoskeletal organisation. This review summarizes the importance of studying cardiomyopathy within the field of muscular dystrophy research, outlines key features of the mdx heart and its suitability as a model system for studying cardiac pathogenesis, and discusses the impact of recent proteomic findings for exploring molecular and cellular aspects of cardiac abnormalities in inherited muscular dystrophies.
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